Opt-in "jamming" (Score 1)

What I would like to see is some form of opt-in "jamming". For example, when I go to a movie theatre, I might sometimes forget to turn off my cell phone. But if there is a device in the theatre that tells your cell phone: you are now in a theatre, then I can tell my cell phone to go to vibrate mode whenever I am in that zone. I.e. the theatre tells you where you are, and it is your responsibility to act on that information accordingly. I should then be able to change my outgoing message, so I'm still available: "Hi you have reached the phone of Joe. I am currently in a movie theatre, and will look like a fool if I answer the phone now, but in case of a real emergency, please press 1, and my phone will ring. Otherwise, please leave a voice mail or text message." I think something like this would greatly help the problem, because currently the caller has no idea that he might be putting the callee in a socially unacceptable position at the time that the call is being placed.